Generic valve drives for an internal combustion engine having a camshaft and having at least one cam follower as well as a first cam that is non-rotatably arranged on the camshaft and with a second cam that is arranged axially adjacent to the first cam are already known. Here, the cam follower is drive-connected in a first position to the first cam of the respective cam group and in a second position to the second cam of the respective cam group.
An adjusting device of the valve drive having a first adjustable engagement peg and having a second adjustable engagement peg interacts in each case with a slotted guide arranged on the camshaft. By way of the adjusting device, the cam follower can be adjusted between the first position and the second position and the valve drive activated. The first slotted guide and the second slotted guide are arranged laterally on the cams on the camshaft. By way of the slotted guide, the engagement pegs which are arranged on the pin spaced next to one another can be adjusted between a basic position and a shifting position. In the basic position, there is no contact with the associated slotted guide while in the shifting position the respective engagement peg interacts with the associated slotted guide.
In order to be able to achieve as high as possible a flexibility during the operation of an internal combustion engine the focus is increasingly on valve drive applications and exhaust brake systems as well as the possibility of a cylinder cutout in order to be able to optimise for example the combustion in a part load operation. In particular parallel applications of exhaust brake operation and cylinder cutout function increasingly raise interest. Systems that are based on the shifting of a roller pin or coupling pin by means of mechanical positive guidance to the camshaft, such as are conceivable for example with cam followers having at least two rocker arms that can be optionally coupled to one another or separated from one another (connectable rocker arms) require a corresponding cam lift for initiating the shifting operation. Because of this, the use of zero lift rounds, via which a cylinder cutout can be brought about for example, is limited. Alternatively, three-stage systems which can switch between a fired, a braking and a cutout mode, is obviously also conceivable but these are complex, critical in terms of installation space and cost-intensive. With so-called axially adjustable cam followers (shifting rollers) a cylinder cutout using a zero lift round is not generally possible.